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How can I control amplitude and phase of signal

Prakash Bharti
Prodigy 90 points
Other Parts Discussed in Thread: PGA855

Hi TI team,

There are few queries of mine:-

I have a AC signal of 36V/0.1A and want to control its amplitude and phase with controller.

How can I do this?

Can you please suggest some circuit through which I can achieve this.

I will connect the circuit with the controller GPIO and with the change of voltage level of on GPIO the amplitude of the AC signal should change.

Also, similarly with change in GPIO voltage level the phase of the AC signal should change.

Thanks & Regards,

Prakash

  • 0
    TI__Genius 11775 points

    Hi Prakash,

    The amplitude is easy; you can use many different architectures to control the gain.  Devices like PGA855 can be used for gains from 1/8 to 16. You mentioned your input amplitude but not the output amplitude - do you want it attenuated or gain up?

    The phase is not so easy.  It may be possible to configure a switchable filter with varying phase response, but the phase will be frequency-dependent and also have impacts on the gain of the filter.  The first question here is; what is the frequency range you are looking at?  Also, is the signal one single frequency, or is there a BW that you expecting to have this delay?

    Regards,
    Mike

  • 0 in reply to Michael Hartshorne
    Prodigy 90 points

    Hi Michael,

    I have AC voltage source of 10V/400Hz. I want to control it's amplitude with the help of controller.

    How can I do this?

    Thanks & Regards,

    Prakash

  • 0 in reply to Prakash Bharti
    TI__Genius 11775 points

    Hi Prakash,

    What amplitude levels do you want to control this signal to?  i.e. 0.1 V to 10 V?  And, what resolution are you looking for?  Do you need only a few gain steps (say 8), then the PGA855 can work.  But, if you need fine gain control (i.e. 128 steps) then a different approach will be necessary.

    Regards,
    Mike

  • 0 in reply to Michael Hartshorne
    Prodigy 90 points

    Hi Michael,

    What amplitude levels do you want to control this signal to?  i.e. 0.1 V to 10 V?. Yes, I want to control in the same way.

    I need 128 steps or greater.

    Thanks & Regards,

    Prakash

  • 0 in reply to Prakash Bharti
    TI__Genius 11775 points

    Hi Prakash,

    The PGA281 is a good choice for this - you can configure this device for the conditions you mentioned above.  Let me know if you have any specific questions about implementing this device.

    Regards,
    Mike